Method and device for determining the actuation position of an adjusting element of a motor vehicle

A device for determining an actuation position of a motor-driven adjusting element of a motor vehicle, the device comprising:

• a rotatable ring magnet;
• a Hall-effect sensor spaced apart from the rotatable ring magnet, the Hall-effect sensor configured to detect time-dependent and/or angle-dependent changes in a magnetic flux density resulting from a rotational motion of the ring magnet, the time-dependent and/or angle-dependent changes being converted into a binary pulse train;
• a comparator circuit having a hysteresis between an upper switching threshold and a lower switching threshold;
• and
• a control device configured to shift the upper and lower switching thresholds toward a center line of the hysteresis,
• wherein the upper and lower switching thresholds are shifted by an amount that corresponds at least to a magnitude of a threshold drift resulting from a heating or cooling of the Hall-effect sensor.

A device, comprising:

• a motor-driven adjusting element of a motor vehicle;
• a rotatable ring magnet;
• a Hall-effect sensor spaced apart from the rotatable ring magnet, the Hall-effect sensor configured to sense a magnetic flux density;
• and
• a control device configured to:
• convert a periodic change in the magnetic flux density sensed by the Hall-effect sensor into a binary pulse train, a pulse being transitioned when an upper switching threshold is positively exceeded and when a lower switching threshold separated from the upper switching threshold by a hysteresis is negatively exceeded;
• and
• reduce the hysteresis following an inactive phase of the Hall-effect sensor, during which phase, the magnetic field is stationary and/or the Hall-effect sensor is deactivated if the magnetic flux density at the start of the inactive phase has exceeded the upper switching threshold by no more than a predefined tolerance range,
• wherein the hysteresis is reduced by lowering the upper switching threshold, and
• wherein the hysteresis is reduced by an amount that corresponds at least to a magnitude of a threshold drift resulting from a heating or cooling of the Hall-effect sensor.